ASSERTION AND REASON
The following questions consist of two statements each : assertion (A) and reason (R). To answer these questions, mark the correct alternative as directed below :
(a) If both A and R are true and R is the correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) If A is true but R is false.
(d) If both A and R are false.
1. Assertion (A) : Vascular cambium is single layered but
appears to be 2-3 layer in thickness due to presence of immediate derivatives.
Reason (R) : Cells of vascular cambium divide by unipolar division to form secondary permanent tissue.
2. Assertion (A) : Cells of the meristematic region enter G0 phase.
Reason (R) : Cells of meristem undergo differentiation to form a particular tissue or organ.
3. Assertion (A) : Germinating seeds respire slowly.
Reason (R) : Germinating seeds require only anaerobic environment for initiations of germination.
4. Assertion (A) : Intercalary meristem helps in elongation of the organs.
Reason (R) : Intercalary meristematic regions are derived from the apical meristem.
5. Assertion (A) : Abnormal type of secondary growth occur in some arborescent monocots.
Reason (R) : In arborescent monocot stem stems, secondary cambium grows in hypodermal region.SHORT ANSWER TYPE QUESTIONS1. Fill in the blanks.
(a) Water is essential for _______ of the growing cells.
(b) Pith cells are living cells, with little _______ and _______ in their walls.
(c) Lateral meristems involved in secondary growth of a plant are _______ and _______.
(d) Strain at the circumference of the stem resulting
from secondary thickening causes epidermis to _______.
2. Summarise the effect of abiotic factors on germination.
3. Differentiate between heart and sap wood.
4. Describe the role of two meristems involved in secondary growth of dicot root.